SCIENCE-GOSSIP. 



ii 



two in number, the anterior one, or ' tractellum,' 

 locomotive and vibratile, the posterior one, or 

 ' gubernaculum ' used for steering, are trailed 

 inactively in the rear during natation, adherent or 

 anchorate by its posterior flagellum in the sedentary 

 condition ; oral aperture distinct, mostly associated 

 with a well-defined tubular pharynx ; endoplasm 

 transparent, granular. Inhabiting salt and fresh 

 water." 



Anisontma grande Ehr. — The body is ovate or 

 oblong, and flattened dorsiventrally. The dorsal 

 surface is convex, the ventral one flat, or more 

 or less concave ; it is rounded posteriorly, and 

 anteriorly becomes narrower ; it is described by 

 Dujardin as pip-shaped. It is about twice as 

 long as broad, and from 20 to 30 microns 

 in length. The cuticular investment is smooth 

 and somewhat hardens, and may be found 

 not decomposed after the death of the animal, 

 The flagella originate a short distance from one 

 another, close to the anterior extremity. The 

 anterior vibratile flagellum, or "tractellum," is 

 slender, and is about the same length as the body ; 

 the posterior one, or " gubernaculum," is three or 

 four times as long as this, and is thick and strong 

 at the base. The oral aperture is near the base 



of this, and communicates with a short tubular 

 pharynx. The contractile vacuole is single, and 

 situated just behind the oral aperture. The 

 endoplast is spherical or ovate, and situated near 



Fig. 12. — Anisonema grande. 

 a, Ventral; b, side view ( x 500). 



the posterior extremity. The free-swimming 

 motion of this animal is straight and steady. It 

 often anchors itself by its posterior flagellum, and 

 swings slowly round and round its point of attach- 

 ment. 



The species is fairly common, and where it does 

 occur, it is often found in large quantities. It may 

 be searched for in ponds and ditch water. 

 (To be continued.) 



SOME FOUNDERS OF GEOLOGY. 



By Edward A. Martin, F.G.S. 



HPHE study of geology is now divided up into 

 so many branches, each of which has its 

 own band of devoted specialists, that there are 

 few men living who are sufficiently authoritative 

 in all branches to be enabled to take wide and 

 general, as well as accurate, views of geological 

 science as a whole. It is with good effect that 

 one can turn, therefore, to Sir Archibald Geikie's 

 "Founders of Geology," and read the history of 

 the early days of geology, when men were in the 

 habit of regarding the subject from a broad 

 all-round point of view. Certainly, through 

 insufficient data, they fell into many and gross 

 errors, but one sometimes wishes there were more 

 nowadays who, as the late President of the 

 Geological Society of London once said of Dr. 

 Wheelton Hinde, dared to deal with the broader 

 questions of geology. Sir Archibald speaks in this 

 book appreciatively of the vast amount of work 

 performed by one of the earliest "founders," 

 viz., Guettard (1715-1786). He was the first 

 actually to construct geological maps, sixteen 

 sheets of a map of France being completed 

 by him. He may be regarded as the father of 

 all our geological surveys. He published writings 

 dealing with the degradation of the land by 



B 



rains, rivers, and sea-action. He showed that 

 the material carried seaward was deposited around 

 the coasts, and distinguished what we now call 

 littoral deposits from those forming farther out at 

 sea. Guettard was, too, the first to discover that 

 in the centre of France was a group of extinct 

 volcanoes. In 1752 he announced to the Academy 

 that he had detected some sixteen or seventeen 

 volcanic cones in the Auvergne, and that he had 

 traced the ancient lava-flows to their now silent 

 craters. In 1770 he read a paper on "Basalt." As 

 his observations in Auvergne practically started 

 the Vulcanist camp, so, says Sir Archibald, his 

 tenets regarding basalt became the watchword of 

 the Neptunists. In regard to his theory of the 

 aqueous origin of basalt, he was thus a prophet of 

 the great Wernerian theory. 



Werner (1749-1817) himself published but little, 

 his opinions being known principally from the • 

 works of his many devoted and enthusiastic 

 pupils, in whom he seems to have instilled a kind 

 of mesmeric attachment. Although it cannot be 

 denied that Werner accomplished good work in 

 some directions, yet "his influence was disastrous 

 to the higher interests of geology." In regard to 

 Wernerism, " never was a system devised in which 



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